Multiple frequency source



Aug. 1, 1944. H, B. DLEAL y MULTIPLE 'FREQUENCY SOURCE Filed Aug. vl7,'1941 2. sheets-sheet 1 Augl, 1944- H; B. DEAL 2,354,800

MULTIPLE FREQUENCY SOURCE l Filed Aug. 7, 1941 2 Sheets-Sheet 2 l /MAMUN DEAL "L I f YBYY TroRNEY Patented Aug. l, 1944 MULTIPLE FREQUENCY SOURCE Harmon B. Deal, Glen Ridge, N. J., assignor to Radio Corporation o! America, a corporation of Delaware Application August 7, 1941, Serial No. 405,758

1 Claim. l (Cl. Z50- 36) The present invention relates generally to an arrangement for producing a plurality of different frequencies from a single master frequency.

More particularly, the invention provides means for producing a plurality of stable frequencies from a standard frequency which may be a crystal controlled oscillator or the sixty-cycle current which is usually available in a commercial light and power supply network. In the latter case it is possible to take advantage of they frequency constancy of the usual commercially available light and power supply current and to utilize it for producing various control frequencies.

It is often desirable and sometimes essential to be able to generate or produce one or more stable control frequencies for use in controlling the operation of one or more remotely situated devices. One such instance arises inthe type of systems shown and described in my United States Patent 2,340,798, which was granted February 1, 1944, wherein there isA described a system for controlling the operation of a radio receiver and/or the operation of an alarm device by means of control frequencies which are usedto modulate the carrier of a broadcasting station and are thereby transmitted to the remote point.

Briefly, according to the present invention, there is obtained froma single master frequency, a plurality of frequencies by actingv upon the master frequency by multiplication and/or division and thereby produce frequencies which may or may notbe integrally related to the master frequency. This object of the invention may be attainedby utilizing -through the operation a selectively operable device combination of' a relatively few multiplication values and/or a'relatively few division valuesl and obtaining therefrom ya relatively large number of frequencies. The various frequencies are selected preferably by changing one or more of the multiplication ratios and/or one or more of thedivision ratios. A particularly important feature of the invention is-'that the various different frequencies may be obtained without the use of selective circuits.

The invention may be more readily understood and carried into effect by considering the following detailed description thereof and the accompanying drawings.

In the drawings:

Figure 1 illustrates in schematic form a preferred circuit arrangement for producing a plurality of different frequencies from a single master frequency in accordance with the present invention; and

Figure 2 illustrates in diagrammatic form a push button manual for the arrangement shown in Figure 1.

Referring more particularly to Figure 1 of the drawings, the standard frequency is referred to as fo and may be impressed upon the line I by connection of line I to any suitable source such as to a commercially available sixty-cycle current power supply network or a crystal controlled os-v cillator. Line I may be connected to line 6 through a circuit including an operable switch su which, when closed, connects line I to line 6. Line I is also connected to the input of a frequency multiplier 3, which may be a frequency doubler, through an operable switch'si arranged so that when switch s1 is closed, the lstandard frequency on line I is fed to the input of frequency multiplier 3. Also, a connection including switch sis is provided between line I and an auxiliary line 2. The outputvof frequency multiplier 3 is connected to line 2 through'a switch sie and to the input of ra second frequency multiplier 4 which rnay also be a frequency doubler, if desired, through an operable switching device sz. The input of frequency multiplier 4 may -be connected also to line 2 through an operable switch S12. It is seen, therefore, that the frequency multiplier 4 may have impressed upon its input, either the output from frequency multiplier 3 by closing switches s1 and s2, or the standard frequency energy from the line Iby closing switches sis and siz. The output of the frequency multiplier 4 is connected to the input of a third frequency multiplier 5 which, if desired, may be a frequency tripler, through an operable switch sa. In addition, the input 'of the frequency multiplier 5 may be connected to line 2 through an operable switching device sis. Accordingly, the input of frequency multiplier 5 may be connected to either the output of frequency multiplier 4 or to the line I depending upon whether switch sa is closed or switches sia and sis are closed.

The output of frequency multiplier 3 may be also connected to line I0, the latter connection being made through an operable switching device ss. In addition,r the output of frequency multiplier 4 may be connected to line IlL'through an operable switching device se; The' output of frequency multiplier '5 may be connected also to line III through kan operable switching device s'z.

An operable switching device s4 is provided between line 6 and line I0 and acts when closed to connect line 6 to line I0.

Furthermore, line Il) is coupled to the input of a frequency divider network I9. While any type of frequency divider network may be utilized, I have found that a divider of the type disclosed in White, U. S. Patent No. 2,113,011, is admirably adapted for the present purposes. In view of the fact that the frequency divider is described in the above referred to patent, a detailed description thereof will not be given herein except to state that various divider ratios may be obtained with such a device by simply changing the ratio of impedances shown connected thereto through the selective operation of switches sa, S9, Sio, and su. These impedances are shown variable to permit adjustments. lt is to be understood that other types of impedance elements may be employed if desired. The output of frequency divider I9 is connected to an amplifier I2 and, if desired, the connection may be made through a filter I I which may be a low pass filter if it is desired, adjusted to prevent the passage of frequencies to the amplifier which are above a certain predetermined frequency.

A few of the various frequencies obtainable by an arrangement such as described above, assuming that frequency multipliers 3 and 4 are frequency doublers and that frequency multiplier 5 is a frequency tripler, are referred to below in connection with the operation of the switching devices.

Closure of switch S14 impresses frequency fo on line 6. Closure of switch s1 makes available energy of double the standard frequency fo across the output of frequency multiplier 3. This double frequency may be fed to the frequency divider network I9 by closing switches si and ss. Closure of switches si and sz makes available across the output of frequency multiplier 4 energy having a frequency four times the standard frequency and this energy will be present on line 8 so that it may be fed to the frequency divider network I9 by closure of switch se. Closure of switches si, s2 and s3 makes available upon line 9 energy having a frequency which is twelve times the standard frequency. This frequency may be impressed upon the line ID through closure of switch sv. Closure of switches sia and sis impresses upon line 9 energy having a frequency which is three times the standard frequency. This energy may be impressed upon the line IIJ by closure of switch s'z. To obtain energy having a frequency which is six times the standard frequency, it is simply necessary to close switches $15,512 and s3 and such frequency will be available upon line 9, whereupon it may be fed to line IU by closing switch si. The frequency of any energy impressed upon line I0 may be divided by the frequency divider I9,

the divider ratio being dependent upon which one f.,

of the switches sa, se, sro and S11 is closed. It should be understood that while only four of such switches have been shown, any number thereof may be provided and arranged so as to Vary the ratio of the impedances and thereby adjust the divider I9 to produce substantially any desired divider ratio.

In the event that the arrangement herein described is to be used for signalling purposes such as described in my aforementioned Patent 2,340,798, line I3 may be connected through suitable circuits to a transmitter and the carrier of the transmitter may be modulated in accordance with any one of the control frequencies.

In arrangements of this type it is convenient to provide a push button manual arranged so that there will be a distinct selectively operable device for each particular frequency capable of being produced by the system and desired to be utilized. One such arrangement is shown in Figure 2 of the drawings wherein for purposes of illustration a plurality of selectively operable push buttons 30-59 inclusive, have been provided. As illustrated, push button 30 when depressed, closes switches S15 and sie. This will permit the standard frequency fo to be fed directly into the input of filter II. Depression of push button 3I causes closure of switches S14, s4, and ss thereby feeding the fundamental frequency or standard frequency through the frequency divider network I9 which is adjusted by closure of switch ss to provide a particular fraction of the standard frequency and feed it to the input of filter network II. Push button 32 when depressed,closes switches sn, s4 and sg which means that the fundamental frequency is fed to the frequency divider I9 and a fraction thereof determined by closure of switch sis is fed to filter network I I. Depression of switch 33 closes switches sn, s4, and sin while closure of switch 34 closes switches S14, s4, and sii. It is believed that the operation of the other push buttons shown in Figure 2 is self-explanatory. Considering Figure 1 again, it should be understood that any one of the switches shown therein may comprise, in fact, a plurality of switches in parallel so that closure of any one of the group produces the same effect as is produced by closure of any other of that group. For example, the switch s1 shown in Figure 1 may comprise sixteen switches (as shown in Figure 2) all connected in parallel. Thus, in Figure 2 depression of any one of push buttons 35-46 and -58 all numbers inclusive, causes the closure of switch si in Figure 1 thereby feeding the standard frequency to frequency multiplier 3.

While the invention has been described in connection with a particular number of frequency multipliers and frequency dividers, it should be understood that their number and construction may be varied in any suitable manner Within the scope of the appended claim.

What I claim is:

A multiple frequency source comprising a, single master frequency source, a plurality of frequency multiplier circuits, an adjustable frequency divider circuit, and manipulative switching means including push buttons singly operable to control a plurality of switch points for adjusting said frequency divider circuit and for selecting a predetermined path through at least one of said multiplier circuits, thereby to obtain any one of a large number of output frequencies, said path being caused to extend from said master source through those of the multiplier and/or divider circuits which are to be utilized and to bypass the other circuits in accordance with the output frequency which is desired.

HARMON B. DEAL. 

